A known method for measuring platelet aggregation uses platelet rich plasma (PRP) samples derived from the plasma component containing a plenty of platelets obtained through weak centrifugation of whole blood collected from a patient, and platelet poor plasma (PPP) samples derived from the plasma component that does not substantially contain platelets obtained through strong centrifugation of whole blood. In this method, a reagent for causing platelet aggregation is added to the PRP sample and the respective light absorption of the PRP sample and the PPP sample is measured, then the platelet aggregation is calculated from the respective light absorptions.
Japanese Laid-Open Patent 2002-82118 discloses a complex measuring apparatus capable of performing platelet aggregation measurements, and measurements of biological components such as blood coagulation and fibrinolytic system substances through latex agglutination reaction. In this complex measuring apparatus, blood platelet aggregation is measured by adding reagent to the PRP sample, and separately loading the PPP sample and PRP sample in complex measuring apparatus.
The complex measuring apparatus disclosed in Japanese Laid-Open Patent 2002-82118 requires the addition of reagent to the PRP sample and loading of the PPP sample and PRP sample separately in the apparatus. The blood platelet aggregation must be calculated using both measurement results obtained by measuring the PRP sample and the PPP sample obtained by processing whole blood samples obtained from the same patient. Therefore, when measuring the PPP sample and PRP sample, it must be confirmed that the PPP sample and the PRP sample to be measured have been collected from the same patient (same whole blood sample). And if such confirmation is inadequate or erroneous confirmation is done, it may cause a mix-up of samples inadvertently.